Pot head



1933- A. G. STEINMAYER 1,928,636

POT HEAD Filed Oct. 14, 1929 Patented Oct. 3, 1933 POT HEAD Alwin G.Stcinmayer, Milwaukee, Wis, assignor to Line Material Company, SouthMilwaukee, Wis., a corporation of Wisconsin Application October 14,1929. Serial No. 399,647

1 Claim.

As is well known in the art, pot heads are employed to keep moisture outof cables where the strands or conductors thereof are separated and comeout of the sheath and this invention, which is a continuation in part ofmy copending application Serial No. 282,712, filed June 4, 1928, relatesparticularly to covers for the pot heads through which the individualconductors extend and has as its primary object to provide means forinterrupting the continuity of the magnetic metal around the conductorsto reduce the magnetic field which exists around the conductors at thecover.

Heretofore this magnetic field or loop has been reduced by slotting thecover adjacent each aperture through which the cable strands extend andfilling the slots with lead or by forming the entire cover of an alloyor non-magnetic metal; but these methods have proven unsatisfactory.Where the cover is formed of an alloy, the cost is relatively large andwhen the lead filled slots are resorted to, the cost is alsoconsiderable, due to the tedious task of melting the lead into theslots. The present invention not only eiiiciently reduces the magneticloop in an inexpensive manner, but also positively precludes thepossibility of moisture entering into the interior of the pot head.

A further object of my invention, therefore, resides in the provision ofa pot head having an insert of brass or other alloy cast into place.

And a still further object of this invention resides in the provision ofan insert formed of nonmagnetic metal which is cast into a pot headcover or the like and which is so designed that when in place it ispositively held against detachment.

With the above and other objects in View which will appear as thedescription proceeds, my invention resides in the novel construction,combination and arrangement of parts substantially as hereinatferdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaim.

In the accompanying drawing I have illus trated one complete example ofthe physical embodiment of my invention constructed according to thebest mode I have so far devised for the practical application of theprinciples thereof,

and in which:

Figure 1 is a view of a pot head embodying my invention, parts thereofbeing broken away and in section to more clearly illustrate structuraldetails;

Figure 2 is a cross sectional view taken through the cover of myimproved pot head structure taken through Figure 1 on the plane of theline 2-2;

Figure 3 is a top plan view of the cover shown detached from the pothead, and

Figure 4 is an enlarged detail perspective view of one of the insertswhich is cast into the cover member.

Referring now more particularly to the accompanying drawing in whichlike numerals designate like parts, the numeral 5 designates the bowl orbody of a pot head of usual construction and having a cover 6 detachablysecured thereto by screws 7 or the like and preferably formed of castiron. A cable 8 extends upwardly into the pot head interior, theadjacent portion of the pot head being connected with the cable sheathin any suitable manner as at 8 and the cable being composed of aplurality of conductors 9 which are separated within the pot head andare brought outwardly through apertures 10 in the cover 6. A suitableinsulating member or bushing 11 is positioned within each aperture 10 ofthe cover to insulate the conductors 9 from the cover member 6. As iscustomary, the interior of the bowl 5 is completely filled with asuitable insulating compound which is inserted into the interior of thebowl through an opening in the cover adapted to be closed by a plug 12.85

The cover being of cast iron, a magnetic loop is set up which encircleseach conductor, especially when alternating current of relatively highamperage is passing through the conductors and to break up and minimizethe undesirable effects of this loop, the present invention utilizesinserts 13 formed of brass or other suitable alloy and substantiallydouble T-shaped having a tapered Web 14, a head 15, and an intermediatetransverse flange 16 formed by ribs extended from oppo- 95 site sides ofthe web, the web 14 extending beyond the ends of the head and ilange asclearly illustrated in Figure 4.

The inserts 13 are cast into the head 6 and thus form substantially anintegral part thereof, being positioned between adjacent apertures 10and forming a continuation of the aperture peripheries. The differencein shrinkage, between the two metals, however, prevents the formation ofa perfect bond therebetween which allows for a diiierence in contractionand expansion of the metals and thus eliminates the possibility ofbreakage, which might occur if a perfect bond existed between the twometals.

It will be noted that the transverse flanges 16 are embedded in thecover, with their bottom surfaces forming continuations of the innersurface. This construction positively prevents detachment of the insertand also strengthens it.

It is also noted that the inner edge portion of the web 14 projectsbeyond the adjacent surface of the cover. This facilitates the castingof the cover, as it centers the insert with respect to the mold andholds it against shifting during pouring.

From the foregoing description taken in connection with the accompanyingdrawing it will be readily apparent to those skilled in the art to whichan invention of this character appertains that I provide a highlyefiicient, positively retained, and inexpensive means for interruptingthe loop of magnetic metal to reduce the magnetic field present instructures of the character described and one so constructed as topreclude the entrance of moisture to the interior of the structure. :fi

What I claim as my invention is:

In combination with a pothead cover formed of magnetic metal and havinga plurality of outlets, an upstanding flange having a slot thereinrunning between the outlets, a substantially T- shaped member ofnon-magnetic material fitting in said slot, means to maintain saidnonmagnetic material within said slot, and downturnecl outer portions onthe T-shaped member fitting around the edges of said upstanding flangeto keep moisture out of the interior of said pothead.

ALWIN G. STEINMAYER.

